120 BACTERIOLOGY. 



The diagnosis is made by finding the parasites 

 in the blood. They can be found by examining either 

 fresh preparations or stained specimens. In the for-- 

 mer the parasites can be seen inside the red blood- 

 corpuscles as colorless bodies containing granules of 

 pigment that are in active motion. In the stained 

 specimens the parasites are motionless, but are much 

 more distinctly seen. 



The spread of malaria is controlled by all meas- 

 ures that aim at the extermination O'f the mosquito. 

 As the mosquito lives and breeds in swamps and ponds, 

 attention should be directed to these places first. The 

 larvae from which the mosquito develops live and grow 

 near the surface of stagnant water. If oil is spread 

 on the water the larvae cannot hatch out into mos- 

 quitoes. Swamps, when it is practical to do so, should 

 be drained or filled in. In districts where malaria is 

 known to exist, the house should be screened. 



TRYPANOSOMES. 



A trypanosome is a long micro-organism, with 

 spirally twisted body. On one side is a membrane the 

 edge of which is cord-like and extends beyond the body 

 to form a whip or flagellum. The wave-like move- 

 ments of the membrane and the movements of the 

 flagellum propel the trypanosome about. The proto- 

 plasm is granular and contains two nuclei. Reproduc- 

 tion takes place by a longitudinal splitting of the 

 whole cell body. The life cycle is not clear, but in 



